Obituary

Allan Bérubé

Allan Bérubé, who has died unexpectedly aged 61, of complications from stomach ulcers, was a pioneering historian of the lives of working-class lesbians and gay men, the people he called "those we have left behind, or out".

In his award-winning study, Coming Out Under Fire: The History of Gay Men and Women in World War II, he described the positive impact that wartime mass mobilisation had on forging gay identity. He also showed that the US policy of barring lesbians and gay men was introduced only in 1942 - and was often overlooked. One gay marine told him: "There is a war on. Who in the hell is going to worry about this?"

Bérubé was born in Springfield, Massachusetts, to working-class French-Canadian parents. His mother, Lorraine, died during childbirth in 1950. His father, Ronald, worked as a broadcasting technician. Bérubé grew up with three younger sisters and his stepmother, Florence, in a mobile home in a series of trailer parks in the north-eastern US.

He began educating himself by reading Encyclopaedia Britannica, and won a scholarship to a boarding school. In 1964 he graduated with honours and won a scholarship as an English major to the University of Chicago, where he became increasingly involved in organising against the Vietnam war. He dropped out in 1968, because of "class panic, lack of money and unfulfilled homosexual desires".

He moved to Boston, where he came out in 1970 through the Student Homophile League meetings at MIT - one of the first gay liberation groups - and then in 1974 to San Francisco, joining a gay male hippy commune in Haight-Ashbury.

Reading Jonathan Ned Katz's monumental anthology, Gay American History (1976), inspired him to begin his own research into still hidden lives, and in 1979 he was one of the founders of the San Francisco Lesbian and Gay History Project. Reading through old newspapers at the library, he became fascinated by a series of stories he discovered about women who had lived as men, and married women. He developed these into a slideshow, Lesbian Masquerade, with which he toured in 1979.

He was given a stash of letters and photographs saved from a house clearance, which were from a group of gay GIs who had been posted at a base in Missouri, and kept in touch as they were moved around the world. Bérubé said: "I sorted them out and had a good cry. It really captured my heart and raised a lot of questions, so I started doing research."

This developed into a new slide show, Marching to a Different Drummer. Many gay veterans would show up and tell their own stories - a joy for Bérubé, who considered his work "a dialogue". He interviewed more than 70 for what became Coming Out Under Fire.

Published in 1990, it was instantly acknowledged as a landmark work. Studs Terkel and Armistead Maupin heaped praise on it, and it won the Lambda literary award and was regularly cited during the 1993 Senate hearings into the US military's policy of barring lesbians and gay men. Senator Edward Kennedy asked Bérubé to submit questions to ask the house committee. He also gave written testimony, arguing that the real "military problem" that should be investigated was not homosexual behaviour, but heterosexual masculinity.

In 1995, Bérubé co-wrote a television documentary with Arthur Dong based on his book, featuring interviews with nine gay veterans. Pointedly subtitled Prejudice in the Military Then and Now, it won a Peabody award.

In the 1990s, he lived in Manhattan, and was active in the politics of Queer Nation, Out/Look, and Sex Panic! A MacArthur Foundation grant in 1996 allowed him to start writing a history of gay men in the Marine Cook and Stewards Union, a leftwing multiracial union for workers on passenger liners, where gay men lived relatively open lives. He said it was in part inspired by anger at a new stereotype of gay equalling "white and well-to-do". He also lectured at Stanford University and the University of California.

In 2001, Bérubé moved to Liberty, a small town in the Catskills, New York, with his lover, John Nelson. A previous partner, Brian Keith, died in 1987. Nelson survives him.

· Allan Ronald Bérubé, gay historian and activist, born December 3 1946; died December 11 2007